Luminance-Based Video Coding for HDR Artifact Reduction

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Solution Overview

Problem

Traditional video coding standards, such as HEVC, struggle to maintain visual quality when encoding and decoding high dynamic range (HDR) images due to limited bit depths and lossy compression, resulting in noticeable visual artifacts, especially in bright and dark areas.

Innovation Solution

The implementation of luminance-dependent signal processing operations in video encoders and decoders, which adapt characteristics like bit depth, filtering, and quantization based on luminance levels, to minimize errors and improve compression efficiency across different regions of an image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional video coding standards (HEVC, H.264/AVC) are used to encode HDR images, then compression efficiency is achieved, but visual quality deteriorates with noticeable artifacts in bright and dark areas

Engineering Contradiction:
Improvecompression efficiencyVSAvoidvisual quality
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The patent applies different signal processing operations to different luminance regions within the image. Specifically, it performs luminance-dependent signal processing where bright areas, midtone areas, and dark areas are processed differently to preserve visual quality in each region while maintaining compression efficiency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes processing parameters based on luminance levels. It determines whether to perform signal processing operations based on luminance characteristics of image regions, and adjusts quantization parameters, filtering operations, and transformation methods according to the luminance range of different areas.

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If post-production images are compressed to reduce data amount for transmission and storage, then data volume is reduced, but coding errors increase causing visual artifacts

Engineering Contradiction:
Improvedata volumeVSAvoidcoding errors
Core Design Contradiction:
Quantity of substanceVSLoss of information

Solution Approach 1:

The patent applies different compression and signal processing operations to different luminance regions. Bright areas, midtone areas, and dark areas undergo different processing to minimize coding errors in each region while achieving overall data reduction.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent performs luminance analysis and determines processing strategies before actual compression. It identifies luminance ranges and selects appropriate signal processing operations in advance to prevent coding errors rather than correcting them after compression.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If uniform signal processing is applied across all luminance levels, then device complexity is reduced, but visual quality deteriorates in specific regions like highlights and shadows

Engineering Contradiction:
Improvesignal processing complexityVSAvoidvisual quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent divides the image into different luminance regions (bright, midtone, dark areas) and applies specific signal processing operations to each region. This localized approach improves visual quality in specific regions without requiring excessively complex uniform processing across the entire image.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes processing parameters based on luminance levels of different regions. It adjusts quantization parameters, filtering strength, and transformation methods according to whether the current processing region is bright, midtone, or dark, optimizing visual quality for each luminance range.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11729400B2Luminance based coding tools for video compression
Publication Date: 2023.08.15 DOLBY LABORATORIES LICENSING CORP
  • US11729400B2 patent drawing
  • US11729400B2 patent drawing
  • US11729400B2 patent drawing

AI summary

Sample data and metadata related to spatial regions in images may be received from a coded video signal. It is determined whether specific spatial regions in the images correspond to a specific region of luminance levels. In response to determining the specific spatial regions correspond to the specific region of luminance levels, signal processing and video compression operations are performed on sets of samples in the specific spatial regions. The signal processing and video compression operations are at least partially dependent on the specific region of luminance levels.